SHE TENSES when the doorbell rings, for it could be an assassin. Taslima Nasreen is nervous at the peephole, doubting her own invisibility behind the door, as she examines each visitor warily before opening the four locks.

'I'm in a cage here. A prisoner,' she said bitterly. She is a Bangladeshi poet and feminist who has a fatwa - a death threat - imposed on her for blasphemy. Islamic zealots are offering a pounds 850 reward for her murder. Unlike Salman Rushdie, who has gone into hiding to escape a similar threat, she lives openly in Dhaka, the Bangladeshi capital. Belatedly, the government offered her protection: two armed policemen at the tower block's entrance who slap down cards lazily.

She gazes sadly through the wrought-iron bars on her balcony. Sounds drift up from the fruit market below: housewives haggling with papaya sellers, the musical bells of the cycle rickshaws. 'I'd give anything to go outside, to sit in a coffee house, to eavesdrop on girls gossiping as they leave their factories, or, best of all, to go to a book shop. But I know that these fundamentalists would attack me,' she said. The fatwa forced her to quit her job as an anaesthetist.

Nasreen is 31 but seems younger, with an air of childish frankness. She smokes cigarettes often but inexpertly, as though it were a habit acquired recently during her captivity. She has been a target of Islamic fanatics for several years because of her outspokenness about sex. She accuses Bangladeshi men of wanting to keep their women 'veiled, illiterate and in the kitchen'.

The candour with which she writes about rape, family violence and orgasm may have shocked Muslim clerics, but it resonated with thousands of housewives and women students. 'I don't write about sex. I write about sexual abuse. Women are used as a commodity,' she said.

She has been divorced three times, and her private life is the subject of much gossip and attack. A dozen malicious books about her, all written by men, were displayed at the last Dhaka book fair, with titles such as Taslima Knows No Shame.

Every month she receives hundreds of letters, mainly from women. 'They ask for advice. They thank me for daring to say the things that they have felt secretly,' she said. But more than a few are death threats. ' 'If you keep writing against Islam, we'll kill you' - that's the message.'

The fatwa has been hanging over her since last October, when Muslim clerics took exception to her novelette Lajja (Shame). It describes how Hindu families in Bangladesh had their homes torched and their daughters raped by Muslims seeking revenge for the 1992 destruction of the Ayodhya mosque in India. A school principal in Sylhet, acting in the name of the Council of Islam's Soldiers, issued the death threat. In December more than 5,000 zealots marched through Dhaka, demanding her death. Lajja sold more than 60,000 copies in Bangladesh before it was banned. Denouncing Nasreen is still a favourite sermon topic in the mosques.

Until recently, Bangladeshis have shown a tolerant faith. But liberals are alarmed by the growing zealotry that has surfaced over Nasreen's writings and in another case, where a woman, falsely accused of adultery, was buried up to her waist in a pit and stoned.

When news of the fatwa reached India, Nasreen became the unlikely champion of Hindu extremists. Passages from her novel, describing how Muslim mobs beat up Bangladeshi Hindus and tore down their temples, were widely circulated. Nasreen was shocked and scared by her unwanted supporters. 'I am against communalism of all kinds,' she said.

Her only forays from her flat are by car, after dark, with the windows rolled up. She refuses to wear a burqaa, the full-length veil, which would allow her to move through the streets unseen. 'How could I?' she said. 'Women must discard their veils.'

In January last year the Bangladeshi government confiscated her passport because, according to immigration officials, 'her books were against religion'. She is fighting to regain her passport through the courts. If she succeeds, Nasreen wants to travel to Britain to visit Rushdie, who has rallied to her defence publicly.

Her new novel, about divorce in the Bangladeshi family, promises to be as controversial as the last.